Power source for a vehicle service cart

ABSTRACT

Systems and methods are disclosed of a service cart for an aircraft or other vehicle, which includes a thermoelectric device capable of generating a current as a result of a temperature differential between a cold compartment of the cart and an ambient environment. The current can be either stored in a battery or other storage device, and used to power one or more electronic components associated with the cart.

This application claims priority to U.S. provisional patent applicationhaving Ser. No. 62/472,245 filed on Mar. 16, 2017. This and all otherreferenced extrinsic materials are incorporated herein by reference intheir entirety. Where a definition or use of a term in a reference thatis incorporated by reference is inconsistent or contrary to thedefinition of that term provided herein, the definition of that termprovided herein is deemed to be controlling.

FIELD OF THE INVENTION

The field of the invention is service trolleys and carts for use intransporting and serving food and beverages, and particularly suchservice carts for use in passenger aircraft or other vehicles.

BACKGROUND

The background description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

It is increasingly common for commercial passenger aircraft toincorporate integrated information systems, such as described inAustralian Patent Application No. 2014201741 (to O'Sullivan andShedden). Such systems typically include a server that collects datafrom and helps to coordinate various aircraft systems, including thegalley. While such systems serve to improve efficiency and streamlineoperations, collection of data from elements within the aircraft(particularly mobile elements) can be challenging, in part because ofthe power and space requirements required for data collection andtransmission from items that are generally designed to minimize bothweight and bulk.

All publications herein are incorporated by reference to the same extentas if each individual publication or patent application werespecifically and individually indicated to be incorporated by reference.Where a definition or use of a term in an incorporated reference isinconsistent or contrary to the definition of that term provided herein,the definition of that term provided herein applies and the definitionof that term in the reference does not apply.

On commercial passenger aircraft, trolleys or carts are frequently usedto transport food and beverages from the galley area to individualpassengers. Such service carts typically do not rely on mechanical orelectronic refrigeration to maintain low temperatures, as the heavypower supplies required are not compatible with the desire to minimizeweight and bulk of such devices. Rather, aircraft food and beverageservice trolleys typically utilize water and/or CO₂ ice in combinationwith insulation to maintain low internal temperatures. An example ofsuch a trolley can be found in U.S. Pat. No. 7,444,830, to Moran andRood. In lacking conventional sources of stored power, however, suchtrolleys are poorly suited for incorporation of electronics suitable foruse with aircraft information systems without the addition ofsignificant weight and bulk.

Thus, there is still a need for providing a lightweight and compactsource of power suitable for use with electronic devices in food andbeverage service trolleys and carts.

SUMMARY OF THE INVENTION

The inventive subject matter provides apparatus, systems and methods inwhich a thermoelectric device is provided that utilizes the temperaturedifference between the interior of an insulated food and beverageservice cart or trolley (which is typically cooled at least in part byphase changes in water and/or CO₂ ice) and the relatively warm ambientenvironment to generate electrical power. The electrical power that isgenerated can then be used to power electronic equipment, or used tocharge a light weight storage device (for example, a supercapacitor)that is subsequently used to power electronic equipment. In a preferredembodiment of the inventive concept, the thermoelectric device is aPeltier device that utilizes the Peltier-Seebeck effect to generate anelectric current in response to a temperature differential.

Although the below discussion focuses on carts or trolleys, it iscontemplated that the inventive subject matter discussed herein could beused in apparatus having similar properties or functions and thatpermits energy harvesting using a Peltier device, for example. Further,while the below discussion focuses on aircraft, it is contemplated thatthe inventive subject herein could be utilized in busses, trains, boats,and other vehicles, as well as free-standing structures or otherlocations where concessions may be served.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of a Peltier element of athermoelectric device.

FIG. 2 illustrates one embodiment of a multiple-Peltier elementthermoelectric device.

FIG. 3A illustrates one embodiment of a food and beverage cart of theinventive concept.

FIG. 3B illustrates an enlarged view of a portion of the cart of FIG.3A.

DETAILED DESCRIPTION

The following discussion provides many example embodiments of theinventive subject matter. Although each embodiment represents a singlecombination of inventive elements, the inventive subject matter isconsidered to include all possible combinations of the disclosedelements. Thus if one embodiment comprises elements A, B, and C, and asecond embodiment comprises elements B and D, then the inventive subjectmatter is also considered to include other remaining combinations of A,B, C, or D, even if not explicitly disclosed.

One should appreciate that the disclosed techniques provide manyadvantageous technical effects including providing a compact andlightweight source of electrical power to a food and beverage servicecart or trolley without compromising its primary functions and features.

In a preferred embodiment of the inventive concept the thermoelectric(TE) device 100 includes a Peltier element 101 that utilizes thePeltier-Seebeck effect, such as that shown in FIG. 1, to generateelectrical power. The Peltier element 101 includes two or more elementsof n-type and p-type doped semiconductor material, 120, 122,respectively, which are connected electrically in series and thermallyin parallel. These thermoelectric elements 120, 122 and their electricalinterconnects are typically mounted between two ceramic substrates thatact as a structure for the device 100 and electrically insulate theelements 120, 122 from one another and from external mounting surfaces.

In embodiments of the inventive concept, the cool side 104 of such adevice 100 would be placed in thermal communication with an interior ofan insulated interior space of a food and beverage service cart, such asshown in FIG. 3, while the heat source side 102 would be in thermalcommunication with the ambient environment. When used in such acombination, the device 100 acts as a small heat pump, moving heat fromone side of the device 100 to the other.

It should be appreciated that multiple Peltier elements 201A, 201B . . .201N can be assembled in a single thermoelectric device 200, as shown inFIG. 2, in order to improve efficiency and/or power generating capacity.Like the element in FIG. 1, the multiple Peltier elements 201A, 201B . .. 201N can be arranged such that a cool side of such the device 200would be placed in thermal communication with an interior of aninsulated interior space of a food and beverage service cart, while thewarm or hot side would be in thermal communication with the ambientenvironment.

Each of the elements 201A, 201B . . . 201N includes two or more elementsof n-type and p-type doped semiconductor material, 220, 222,respectively, which are connected electrically by an interconnect 224.The elements 201A, 201B . . . 201N are mounted between two ceramicsubstrates 202 and 204, with substrate 202 facing the “hot” side andsubstrate 204 facing the “cool” side.

The device 200 can include an electrical connection 210 through whichcurrent generated by the device 200 can be sent to battery or otherstorage device, for example.

FIGS. 3A-3B shows an example of a food and beverage service cart 300 ofthe inventive concept. As shown, the food and beverage cart 300 includesa cold compartment 302, which in some embodiments can contain dry iceand provide cooling for the interior of the cart 300 through sublimationof CO₂ ice. The large temperature differential between the coldcompartment 302 and the ambient environment used by thermoelectricdevice 310 that incorporates one or more Peltier elements, such as thatshown in FIG. 2, advantageously provides a lightweight source ofelectrical energy.

The cold compartment 302 is preferably an insulated interior space ofthe cart 300, which is maintained at a reduced temperature that is atleast 5° C. below that of the ambient environment. Such space can be acabinet or compartment of the trolley/cart 300. In other embodiments,the insulated interior space can be a separate, removable enclosure thatis supported by the trolley/cart 300. The reduced temperature can beprovided by the inclusion of a low-temperature material, such as wateror CO₂ ice, within the cold compartment 302. Melting and/or sublimationof such water or CO₂ ice within the cold compartment 302 maintains thereduced temperature. Alternatively, the reduced temperature can beprovided by chilling the trolley/cart 300 or a portion thereof, such aswhile the trolley/cart 300 is locked in place in the aircraft, or priorto being moved to the aircraft from a remote location. In someembodiments the cold compartment 302 can include components that serveas heat reservoirs (for example, phase change materials) to enhance theeffect of such chilling.

The thermoelectric device 310 is preferably in thermal communicationwith both the cold compartment 302 and the ambient environment. Suchthermal communication can be direct, for example by direct contact of atleast a portion of the thermoelectric device 310 with the coldcompartment 302 (for example, by integration into a portion of a wall ofthe cold compartment 302). Alternatively, thermal communication with thethermoelectric device 310 can be indirect. Such indirect thermalcommunication can be passive, for example thermal communication providedby thermally conductive materials placed between the interior of thecold compartment 302 and the thermoelectric device 310 and/or betweenthe ambient environment and the thermoelectric device 310. In otherembodiments indirect thermal communication can be active, for examplethrough the provision of devices such as heat pipes.

A thermoelectric device suitable for use in the inventive concept arecapable of generating electrical energy from a temperature differentialof 5° C. or more, and preferably from a temperature differential of fromabout 5° C. to about 20° C. or more. Suitable thermoelectric devices canbe solid state devices, such as a Peltier element or thermocouple.Alternatively, suitable thermoelectric devices can include mechanicalelements, such as a Sterling engine in combination with a generator.

In some embodiments, the service trolley or cart 300 can include alightweight energy storage device 320 that is in electricalcommunication with the thermoelectric device 310. Such an energy storagedevice 320 advantageously permits the accumulation of electrical powerfrom the thermoelectric device 310 for an extended period of time, whichcan in turn be expended rapidly by a high drain electronic device (suchas a near field, RF, and/or Bluetooth transmitter). Thus, energygenerated from the device 310 can be provided via an electricalconnection to the device 320.

Suitable lightweight energy storage devices include lightweightbatteries, capacitor banks, and supercapacitors. In a preferredembodiment, the energy storage device is a supercapacitor that is inelectrical communication with the thermoelectric device 310 for purposesof charging and with an electronic device 320 that utilizes the storedelectrical energy.

The continuous generation of electrical power advantageously permits theuse of a relatively small and lightweight storage device for such power,as it is continuously replenished as the service cart is in use. Thestored electrical power can in turn be utilized to power electronicdevices 330 associated with the food and beverage service cart, such aspowering sensors and a transceiver to provide updated status informationabout the cart to a central server. Such information could include atemperature inside one or more compartments of the cart, salesinformation for purchased product, an inventory of products within thecart, and so forth.

As noted above, electrical power generated from such thermoelectricdevices can be utilized by one or more electronic devices associatedwith a food and beverage service cart. Such electronics can, forexample, be utilized to record or monitor transactions (such as a pointof sales device), read RFID chips, read magnetic strips of debit/creditcards, monitor and/or report inventory, and/or transmit and receiveinformation from an on-board server. In some embodiments the electronicdevice can include a near field, WiFi, RF, and/or Bluetooth transceiver.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

As used herein, and unless the context dictates otherwise, the term“coupled to” is intended to include both direct coupling (in which twoelements that are coupled to each other contact each other) and indirectcoupling (in which at least one additional element is located betweenthe two elements). Therefore, the terms “coupled to” and “coupled with”are used synonymously.

Unless the context dictates the contrary, all ranges set forth hereinshould be interpreted as being inclusive of their endpoints andopen-ended ranges should be interpreted to include only commerciallypractical values. Similarly, all lists of values should be considered asinclusive of intermediate values unless the context indicates thecontrary.

The recitation of ranges of values herein is merely intended to serve asa shorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value with a range is incorporated into the specification asif it were individually recited herein. All methods described herein canbe performed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g. “such as”) provided with respectto certain embodiments herein is intended merely to better illuminatethe invention and does not pose a limitation on the scope of theinvention otherwise claimed. No language in the specification should beconstrued as indicating any non-claimed element essential to thepractice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember can be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. One ormore members of a group can be included in, or deleted from, a group forreasons of convenience and/or patentability. When any such inclusion ordeletion occurs, the specification is herein deemed to contain the groupas modified thus fulfilling the written description of all Markushgroups used in the appended claims.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the spirit of theappended claims. Moreover, in interpreting both the specification andthe claims, all terms should be interpreted in the broadest possiblemanner consistent with the context. In particular, the terms “comprises”and “comprising” should be interpreted as referring to elements,components, or steps in a non-exclusive manner, indicating that thereferenced elements, components, or steps may be present, or utilized,or combined with other elements, components, or steps that are notexpressly referenced. Where the specification claims refers to at leastone of something selected from the group consisting of A, B, C . . . .and N, the text should be interpreted as requiring only one element fromthe group, not A plus N, or B plus N, etc.

What is claimed is:
 1. A portable service cart for an aircraft or othervehicle that generates electrical energy from a temperature differentialbetween the cool interior of the service cart and the warmer ambientenvironment, comprising: an interior space having a temperature that isat least 5° C. below a temperature of an ambient environment due to icecomposed of water or CO₂ that is disposed within the interior space; athermoelectric device comprising a first substrate and a secondsubstrate, and two or more elements of n-type and p-type dopedsemiconductor material disposed between the first substrate and thesecond substrate, wherein the first substrate is exposed to the warmerambient environment and the second substrate is coupled to the coolerinterior space such that the thermoelectric device is in thermalcommunication with both the cooler interior space and the warmer ambientenvironment; and an electronic device electrically coupled to thethermoelectric device, and selected from the group consisting of a pointof sale device, an RFID reader, a magnetic strip reader, and a wirelesstransceiver; wherein, during operation, the thermoelectric devicegenerates a current to power the electronic device, and wherein thecurrent is generated by utilizing a Seebeck effect from a temperaturegradient between the cooler temperature of the interior space and thewarmer temperature of the ambient environment by moving heat from thewarmer ambient environment to the cooler interior space.
 2. The servicecart of claim 1, further comprising an energy storage device that is inelectrical communication with the thermoelectric device and with theelectronic device, and wherein the energy storage device is configuredto store at least some of the current generated by the thermoelectricdevice for use in powering the electronic device.
 3. The service cart ofclaim 2, wherein the energy storage device is selected from the groupconsisting of a battery, a capacitor, and a supercapacitor.
 4. Theservice cart of claim 1, wherein the interior space comprises aninsulated space compatible with ice composed of water or CO₂.
 5. Theservice cart of claim 1, wherein the temperature of the interior spaceis between 5° C. to 20° C. below the temperature of the ambientenvironment.
 6. A portable service cart for an aircraft or other vehiclethat generates electrical energy from a temperature differential betweenthe cool interior storage space of the service cart and the warmerambient environment, having at least one electronic component selectedfrom the group consisting of a point of sale device, an RFID reader, amagnetic strip reader, and a wireless transceiver, comprising: aninterior storage space having a first compartment configured to receiveice composed of water or CO₂, such that the interior storage space has atemperature that is 5° C. to 20° C. below a temperature of an ambientenvironment; wherein the service cart comprises a second compartmentconfigured to store a plurality of service products; a thermoelectricdevice comprising a first substrate and a second substrate, and two ormore elements of n-type and p-type doped semiconductor material disposedbetween the first substrate and the second substrate, wherein thethermoelectric device is disposed on the service cart such that thesecond substrate is in thermal communication with the cooler firstcompartment of the interior storage space and the first substrate is incommunication with the warmer ambient environment, and wherein thethermoelectric device is configured, during operation, to generate acurrent by utilizing a temperature gradient between the below ambienttemperature of the first compartment and the warmer temperature of theambient environment by moving heat from the warmer ambient environmentto the cooler interior storage space; and an energy storage device thatis in electrical communication with the thermoelectric device, andconfigured to store at least some of the current generated by thethermoelectric device; the at least one electronic component beingelectrically coupled with the thermoelectric device or the energystorage device; wherein the current generated by the thermoelectricdevice powers the at least one electronic component.
 7. The service cartof claim 6, wherein the electronic device is electrically coupled to theenergy storage device, and wherein the electronic device is powered bythe energy store device.
 8. The service cart of claim 6, wherein theenergy storage device is selected from the group consisting of abattery, a capacitor, and a supercapacitor.